If you want the button to be placed on the face of a block, you would have to set the block space next to the command block on the side to a button. The button isn't attached to the block when you place it; it is actually occupying the block space next to it. That is why you can't place a block in the same coordinates as a button. It is simply a type of special block.

first, change the command to be whole numbers, no .5's make the command place on the block to the south of that block, and at the end of the command add 3 at the end of the command
i think this would be the command, /setblock 3 8 -58 77 3
the coordinates might be wrong, but test around, i know they have to be whole numbers though